CN112352033B - Process for preparing hydrocarbon mixtures exhibiting a unique branched structure - Google Patents

Abstract

Provided herein is a unique process that produces saturated hydrocarbon mixtures with well controlled structural properties that address performance requirements driven by stricter environmental and fuel economy regulations for automotive engine oils. The method allows for control of the branching properties of the hydrocarbon molecules so as to consistently provide compositions having a surprising correlation of CCS viscosity (ASTM D5329) and Noack volatility (ASTM D5800) at-35 ℃. The process comprises providing a specific olefin feed, oligomerizing in the presence of a BF3 catalyst, and hydroisomerizing in the presence of a noble metal impregnated 10-membered ring zeolite catalyst.

Description

Process for preparing hydrocarbon mixtures exhibiting a unique branched structure

Technical Field

Processes have been developed for preparing high performance hydrocarbon mixtures that have unique combination characteristics and which exhibit excellent low temperature performance and volatility.

Background

Base stocks are often used in the production of a variety of lubricants, including automotive lubricating oils, industrial oils, turbine oils, lubricating esters, metal working fluids, and the like. They are also used as process oils, white oils and heat transfer fluids. Finished lubricants are generally composed of two components: base oils and additives. The base oil, which may be a base stock or a mixture of base stocks, is the major component in these finished lubricants and makes a significant contribution to the properties of the finished lubricant such as viscosity and viscosity index, volatility, stability and low temperature properties. Typically, a small number of base stocks are used to make a wide variety of finished lubricants by varying the mixture of individual base stocks and individual additives.

The American Petroleum Institute (API) classifies base stocks into five categories based on their saturates content, sulfur level, and viscosity index (table 1 below). I. Group II and III base stocks are mostly obtained from crude oil via extensive processing such as solvent refining for group I and hydrotreating for group II and group III. Certain group III basestocks may also be produced from synthetic hydrocarbon liquids via gas-to-liquid processes (GTL) and obtained from natural gas, coal or other fossil resources. Group IV basestocks (polyalphaolefins (PAOs)) are produced by the oligomerization of alpha olefins such as 1-decene. Group V basestocks include all basestocks not belonging to groups I-IV such as naphthenic basestocks, polyalkylene glycols (PAGs) and esters. Most feedstocks used for large-scale base stock manufacture are non-renewable.

TABLE 1 API base oil classification (API 1509 appendix E)

Automotive engine lubricating oils are by far the largest market for basestocks. The automotive industry has placed more stringent performance specifications on engine oils due to the requirements for lower emissions, longer drain intervals, and better fuel economy. In particular, automotive OEMs (original equipment manufacturers) have driven the use of lower viscosity engine oils, such as 0W-20 to 0W-8, to reduce friction losses and achieve fuel economy improvements. The use of group II in 0W-xx engine oils is highly limited, as formulations blended with these base stocks fail to meet the performance specifications for 0W-xx engine oils, which results in increased demand for group III and group IV base stocks.

Group III basestocks are produced primarily from Vacuum Gas Oil (VGO) by hydrocracking and catalytic dewaxing (e.g., hydroisomerization). Group III base stocks may also be produced by catalytic dewaxing of slack wax from solvent refining or by catalytic dewaxing of fischer-tropsch synthesized waxes derived from natural gas or coal based raw materials (also known as gas to liquid base stocks (GTL)).

Methods of making group III base stocks starting from VGO are discussed in U.S. patent nos. 5993644 and 6974535. The boiling point profile of group III basestocks is typically higher than PAOs of the same viscosity, which results in them having a higher volatility than PAOs. In addition, group III basestocks typically have a higher cold start viscosity (i.e. dynamic viscosity, CCS, measured according to ASTM D5293) than group IV basestocks at the same viscosity.

GTL base stock processing is described in U.S. patent nos. 6420618 and 7282134, and U.S. patent application publication No. 2008/0156697. For example, the latter publication describes a process for producing base stocks from fischer-tropsch synthesis products, a fraction of which having a suitable boiling point range is subjected to hydroisomerisation to produce GTL base stocks.

The structure and properties of GTL base stocks are described, for example, in U.S. patent nos. 6090989 and 7083713, and U.S. patent application publication No. 2005/0077208. Lubricant base stocks having optimized branching with alkyl branches concentrated toward the center of the molecule to improve the cold flow properties of the base stock are described in U.S. patent application publication 2005/0077208. However, the pour point of GTL base stocks is typically poorer than PAO or other synthetic hydrocarbon base stocks.

Another concern for GTL base stocks is a severely limited commercial supply due to the prohibitively large capital requirements for new GTL manufacturing facilities. There is also a need to obtain low cost natural gas to profitably produce GTL base stocks. Furthermore, since GTL base stocks are typically distilled from isomerate oil having a broad boiling point profile, the process produces a relatively low yield for base stocks of the desired viscosity compared to typical PAO processes. Due to these monetary and yield limitations, there is currently only a single manufacturing facility for group III + GTL base stocks, which exposes GTL-using formulations to the risk of supply chain and price fluctuations.

Polyalphaolefins (PAO) or group IV basestocks are prepared by reacting a Polyalphaolefin (PAO) or group IV basestock in a Friedel-crafts catalyst such as AlCl ₃ 、BF ₃ Or BF ₃ Alpha-olefins are polymerized in the presence of the complex. For example, 1-octene, 1-decene, and 1-dodecene have been used to make PAOs with a wide range of viscosities ranging from low viscosity at 100 ℃ with low molecular weight and about 2cSt to high molecular weight viscous materials with viscosity at 100 ℃ exceeding 100 cSt. The polymerization reaction is typically carried out in the absence of hydrogen; the lubricant range product is thereafter finished or hydrogenated to reduce residual unsaturation. Methods of producing PAO-based lubricants are disclosed in, for example, U.S. patent nos. 3382291; 4172855; 3742082; 3780128, respectively; 3149178, respectively; 4956122, respectively; 5082986; 7456329, respectively; 7544850, respectively; and U.S. patent application publication 2014/0323665.

To meet the increasingly stringent performance requirements of automotive engine oils and other modern lubricants, low viscosity polyalphaolefin base stocks derived from 1-decene are particularly favored. They are used in lubricant formulations either alone or blended with other mineral base stocks. However, 1-decene-based polyalphaolefins can be prohibitively expensive due to the limited supply of 1-decene. Attempts to overcome the availability limitations of 1-decene have resulted in the production of PAO from mixed alpha olefin feeds from C8-C12, which reduces the amount of 1-decene required to impart the properties. However, they still do not completely eliminate the need to provide 1-decene as the primary olefin feedstock due to performance requirements.

Alternatively, PAOs made with linear alpha olefins in the C14-C20 range have unacceptably high pour points that are not suitable for use in a variety of lubricants, including 0W-xx engine oils.

Therefore, there remains a need for a cost-effective manufacturing process that produces base stock compositions with excellent properties for use in the most demanding automotive and other lubricant applications, and such properties include one or more of the following: viscosity, Noack volatility, and low temperature flow.

In addition to the technical needs of the automotive industry, environmental awareness and regulations are driving manufacturers to use renewable raw materials and materials in the production of base stocks and lubricants. It would be very desirable to be able to provide the desired base stocks while also exploiting the use of renewable feedstocks.

Summary of The Invention

The present invention relates to a unique process that produces saturated hydrocarbon mixtures with well controlled structural properties that address performance requirements driven by more stringent environmental and fuel economy regulations for automotive engine oils. The method allows for control of the branching properties of the hydrocarbon molecules so as to consistently provide compositions having the surprising correlation of CCS viscosity (ASTM D5329) and Noack volatility (ASTM D5800) at-35 ℃.

In one aspect, the process of the present invention comprises providing an olefin feedstock of C14 to C20 olefins having less than 40 wt% branched olefins and greater than 50% alpha olefins. The feedstock is oligomerized in the presence of a boron trifluoride catalyst at a reaction temperature of 20-60 ℃. The oligomerized product is then hydroisomerized in the presence of a noble metal impregnated 10-membered ring zeolite catalyst.

The product formed is a saturated hydrocarbon mixture, more than 80% of the molecules having an even number of carbon numbers (according to FIMS). When the hydrocarbon mixture is analyzed by carbon NMR, it exhibits a branching characteristic BP/BI ≧ 0.6037 (internal alkyl branching per molecule) +2.0, and has on average at least 0.3-1.5 methyl branches per molecule.

In another aspect, the process further comprises recovering the product of the oligomerization reaction and removing unreacted monomer as olefin from the product prior to the hydroisomerization. The recovered product from which unreacted monomers have been removed is then separated into two product fractions, one of which contains greater than 95 wt% dimers having a maximum carbon number of 40, and one of which contains greater than 95% trimers and higher oligomeric compounds having a minimum carbon number of 42. The two fractions are separately hydroisomerized. In yet another aspect, the separated dimer fraction comprising greater than 95 wt% dimer, if hydrogenated without hydroisomerization, has a branching proximity of from 27 to 35.

Provided in another aspect is a process that provides an olefin feedstock comprising less than 8 wt% branched monomeric olefin and greater than 90 wt% monomeric alpha olefin, and the monomeric olefin has a carbon number from C14 to C20. The oligomerization utilizes an olefin feedstock at a temperature of 20-60 ℃ at BF ₃ And BuOH/BuAc co-catalyst in a semi-batch or continuous stirred tank reactor at a reaction residence time of 60 to 180 minutes. Recovering a product from the oligomerization reaction, and removing unreacted olefin monomer by distillation. Recovering a bottoms product from the distillation and subjecting said product to a noble metal impregnated one dimensional 10 member ring zeolite at a pressure of 100-; at temperatures of 290 ℃ and 350 ℃; and 500 ℃ hydrogen flow of 3500 scf/bbl. After hydroisomerization, the product is distilled into two fractions. One fraction contains greater than about 95 wt% dimers, and a second fraction contains greater than about 95 wt% trimers and higher oligomers. In another aspectThe product recovered from the oligomerization reaction has unreacted monomeric olefins removed by distillation, and the bottoms are hydrogenated and then hydroisomerized prior to the final production distillation.

Drawings

FIG. 1 shows the correlation between BP/BI and internal alkyl branching per molecule for various hydrocarbons including low viscosity PAO made from 1-decene and 1-dodecene, GTL base oils, and hydroisomerized hexadecene oligomers. The straight line in the figure depicts the equation BP/BI ═ 0.6037 (internal alkyl branch per molecule) + 2.0.

FIG. 2 shows the correlation between BP/BI and 5+ methyl branches per molecule for various hydrocarbons including low viscosity PAO made from 1-decene and 1-dodecene, GTL base oils, and hydroisomerized hexadecene oligomers. It demonstrates that the 5+ methyl branch per molecule of the hydrocarbon mixture disclosed in this patent falls within a unique range of 0.3 to 1.5.

FIG. 3 shows the correlation between NOACK volatility and CCS at-35 ℃ for various hydrocarbons including low viscosity PAO made from 1-decene and 1-dodecene, GTL base oils, group III base oils, and hydroisomerized hexadecene oligomers. The solid and dashed lines depict the upper and lower limits of Noack exhibited by the unique hydrocarbon mixtures of the present invention relative to CCS at-35 c, which are Noack 2750 (CCS at-35 c), respectively ^(-0.8) +2 and NOACK 2750 (CCS at-35 ℃), respectively ^(-0.8) -2。

FIG. 4 depicts an embodiment of the process of the present invention wherein the dimer product and trimer product are separated after hydroisomerization. The oligomers are also hydrogenated prior to hydroisomerization.

FIG. 5 depicts another embodiment of the process of the present invention wherein the dimer product and trimer product are separated after hydroisomerization. The oligomers are not saturated prior to the hydroisomerization step.

Figure 6 depicts an embodiment of the process of the present invention wherein the dimer product and trimer + product are saturated and separated prior to hydroisomerization. Each product was then separately hydroisomerized.

Fig. 7 depicts a variation of the process of fig. 6, wherein the oligomer is not hydrogenated prior to separation and hydroisomerization.

Detailed description of the invention

Disclosed herein is a process for preparing a saturated hydrocarbon mixture having a unique branched structure characterized by NMR, which makes it suitable for use as a high quality synthetic base stock. The process includes oligomerizing a C14 to C20 olefin to form an oligomerization product consisting of unreacted monomer, dimer (C28 to C40), and trimer and higher oligomers (. gtoreq.C 42). The unreacted monomers can be distilled off so that they can be reused in the subsequent oligomerization. The remaining oligomers are then hydroisomerized to achieve a final hydrocarbon mixture having a unique branching structure.

In particular, according to FIMS, the hydrocarbon mixture comprises more than 80% of molecules having an even number of carbon numbers. The branching characteristics of the hydrocarbon mixture by NMR indicate BP/BI ≧ 0.6037 (internal alkyl branching per molecule) + 2.0. Further, on average, at least 0.3 to 1.5 internal methyl branches are located more than four carbons from the terminal carbon. Saturated hydrocarbons having this unique branched structure exhibit a surprising correlation of cold cranking simulated viscosity (CCS) versus Noack volatility, which is beneficial for blending low viscosity automotive engine oils.

Provided herein are processes or methods for producing hydrocarbon mixtures having unique branching structures and associated beneficial properties. The hydrocarbon mixtures can be synthesized via olefin oligomerization to achieve the desired carbon chain length, followed by hydroisomerization to improve their cold flow properties such as pour point and CCS, among others.

In one embodiment, olefins having 14 to 20 carbons in length are oligomerized in the presence of a boric trifluoride catalyst to form an oligomer mixture. The olefins may be derived from naturally occurring molecules such as crude oil or natural gas based olefins, or from ethylene polymerization. In some variations, about 100% of the carbon atoms in the olefin feedstock described herein may be derived from a renewable carbon source. For example, alpha-olefin monomers can be produced by oligomerizing ethylene obtained from the dehydration of ethanol produced from a renewable carbon source. In some variations, the alpha-olefin monomer may be produced by dehydration of a non-ethanol primary alcohol produced from a renewable carbon source. The renewable alcohols can be dehydrated to olefins using gamma alumina or sulfuric acid. In some embodiments, the modified or partially hydrogenated terpene feedstock from a renewable resource is combined with one or more olefins from a renewable resource.

The mixture of C14-C20 olefins used to produce the olefin feedstock may be selected from 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-eicosene (and/or optionally branched structural isomers of these olefins) and/or internal olefins derived from linear internal or branched internal pentadecenes, hexadecenes, heptadecenes, octadecenes, and eicosenes. In one embodiment, the olefin monomers of the feed mixture may be selected from the group consisting of unsaturated linear alpha olefins, unsaturated linear internal olefins, branched alpha olefins, branched internal olefins, and combinations thereof. In yet another embodiment, the olefin monomers of the feed mixture may comprise a mixture of linear alpha olefins and/or linear internal olefins. According to certain embodiments, the longer linear paraffin branches produced from C14 to C20 olefins increase the VI of the oligomers and decrease the CCS, while the pour point of the oligomers may be decreased by introducing branches via dimer isomerization.

In one embodiment of the invention, the olefin feed consists of 14-20 carbon long olefins containing less than 40 wt% branching content. In yet another embodiment of the present invention, the olefin feed comprises less than 30% branched content of olefins. In yet another embodiment, the olefin feedstock comprises less than 20% branched content olefins. In yet another embodiment, the olefin feedstock comprises less than 8% branched content olefins. In a preferred embodiment, the olefin feed comprises less than 3 wt% branching content. Branching in the olefin will reduce the linearity of the oligomers formed by the oligomerization reaction. Branching imparted to the oligomer by the branched olefin will reduce the viscosity index without sufficiently reducing cold flow properties such as pour point and CCS.

In one embodiment of the invention, the olefin feed contains at least 50% alpha olefins. In yet another embodiment, the olefin feedstock contains at least 70% alpha olefins. In yet another embodiment, the olefin feedstock contains at least 80% alpha olefins. In a preferred embodiment, the olefin feed contains at least 90% alpha olefins. Oligomerization of an olefin feedstock without sufficient alpha olefin content will reduce the linearity of the oligomer. Depending on the position of the double bond on the carbon chain of the monomer feed, the branching proximity of the oligomer can be reduced compared to oligomers made from alpha olefins of equal chain length. While the presence of long chain branches will reduce pour point, it will also result in an undesirable decrease in viscosity index and an increase in CCS.

In addition to the olefin feedstock, the oligomerization conditions have a strong influence on the structure and properties of the oligomer product. In one embodiment, the C14-C20 olefin monomer is at BF ₃ And/or BF promoted with a mixture of alcohols and/or esters, e.g. linear alcohols and alkyl acetates ₃ Oligomerized in a Continuous Stirred Tank Reactor (CSTR) in the presence of an average residence time of 60 to 400 minutes. In another embodiment, the C14-C20 olefin monomer is at BF ₃ And/or facilitated BF ₃ Oligomerized in the presence of a CSTR with an average residence time of 90 to 300 minutes. In yet another embodiment, the C14-C20 olefin monomer is at BF ₃ And/or facilitated BF ₃ Oligomerisation in the CSTR in the presence with an average residence time of 120-. The oligomerization reaction temperature may be from 10 ℃ to 90 ℃. In a preferred embodiment, however, the temperature is maintained between 15 ℃ and 75 ℃ and most preferably between 20 ℃ and 60 ℃ for the duration of the reaction. The reaction temperature was found to have a strong influence on the degree of isomerization that takes place during the oligomerization process. Higher temperature oligomerization will increase isomerization and result in a more branched oligomer product, as evidenced by a decrease in the proximity of the branches of the saturated dimer intermediate. In the case where the saturated dimer intermediate is defined as an oligomeric dimer, it has been separated into by distillation<5% trimer or larger oligomers and hydrogenated without isomerization. Such branched dimers do not have the desired structure such as 5+ methyl branches per molecule nor do they have the linearity required for use as a desirable hydroisomerization feed, i.e., with a catalyst fromOligomers produced at too high a temperature will yield undesirable physical properties such as lower viscosity index and higher Noack volatility after hydroisomerization compared to those obtained by hydroisomerizing a-tion of the larger linear dimer fraction to the same pour point. The direct effect of oligomerization temperature is illustrated in examples 14-16.

If the dimer moiety is to be saturated to a Br index of less than 100mg Br ₂ 100g (ASTM D2710), then the oligomerization temperature and residence time within the CSTR need to be properly controlled to ensure that the Branching Proximity (BP) of the dimer portion (C28-C40) of the oligomerization product is 25 to 35, preferably 27 to 35, more preferably 27 to 33, and most preferably 28 to 32. Too low a branching proximity prior to hydroisomerization will result in an isomerized hydrocarbon mixture falling below the solid line of fig. 1, and will produce a less desirable higher CCS viscosity value at-35 ℃ for a given Noack volatility to meet the range shown in fig. 3. Conversely, too high a branching proximity would require more isomerization to reach an acceptable pour point, which would increase both Noack volatility and CCS at-35 ℃.

In one embodiment, the unsaturated oligomer product is distilled to remove unreacted monomer as olefin. For example, the unreacted monomer may be separated from the oligomer product, e.g., via distillation, and may be recycled back into the olefin feed for oligomerization thereof.

The oligomer product is then hydroisomerized to provide the additional branching needed to achieve the desired branching characteristics. In one embodiment, the entire oligomer product, including both dimers (C28-C40) and heavier oligomers (. gtoreq.C 42), is hydroisomerized prior to separation by distillation. The hydroisomerized product is then separated by distillation into the final hydrocarbon product. In another embodiment, the dimer and heavier oligomers are fractionated and hydroisomerized, respectively.

Hydroisomerization catalysts useful in the present invention typically comprise a shape selective molecular sieve, a metal or mixture of metals that is catalytically active for hydrogenation, and a refractory oxide support. The presence of the hydrogenation component results in an improvement in product stability. Typical catalytically active hydrogenation metals include chromium, molybdenum, nickel, vanadium, cobalt, tungsten, zinc, platinum and palladium. Platinum and palladium are particularly preferred, and platinum is most preferred. If platinum and/or palladium are used, the metal content is typically from 0.1 to 5 wt%, usually from 0.1 to 2 wt% and not more than 10 wt% of the total catalyst. Hydroisomerization catalysts are discussed, for example, in U.S. patent nos. 7390763 and 9616419 and U.S. patent application publication nos. 2011/0192766 and 2017/0183583.

The conditions of the hydroisomerization are tailored to achieve an isomerized hydrocarbon mixture having the particular branching properties described above, and will therefore depend on the characteristics of the feed used. The reaction temperature is generally from about 200 ℃ to 400 ℃, preferably from 260 ℃ to 370 ℃, most preferably from 288 ℃ to 345 ℃, and the Liquid Hourly Space Velocity (LHSV) is generally about 0.5h ^-1 To about 5h ^-1 . The pressure is typically from about 15psig to about 2500 psig, preferably from about 50psig to about 2000psig, more preferably from about 100psig to about 1500psig, and most preferably 100psig to 800 psig. The low pressure provides enhanced isomerization selectivity which results in greater isomerization and less cracking of the feed, thus resulting in increased yields of hydrocarbon mixtures in the base stock boiling range.

Hydrogen is present in the reaction zone during the hydroisomerization process, typically in a hydrogen to feed ratio of about 0.1 to 10MSCF/bbl (thousand standard cubic feet per cylinder), preferably about 0.3 to about 5 MSCF/bbl. Hydrogen may be separated from the product and recycled to the reaction zone.

In one embodiment, an additional hydrogenation step is added prior to the hydroisomerization to protect the downstream hydroisomerization catalyst. In another embodiment, an additional hydrogenation or hydrofinishing step is added after the hydroisomerization to further improve the saturation and stability of the hydrocarbon mixture.

The hydroisomerized hydrocarbon mixture comprises dimers of carbon numbers C28-C40, and a mixture of carbon numbers C42 and larger trimers +. Each of the hydrocarbon mixtures will exhibit a BP/BI ≧ 0.6037 (internal alkyl branching) ± 2.0 per molecule, and an average of 0.3 to 1.5 methyl branches per molecule at the fifth or greater position. Importantly, at least 80% of the molecules in each composition also have an even number of carbon numbers,it was determined by FIMS. In another embodiment, each hydrocarbon composition will also exhibit a correlation of Noack and CCS at-35 ℃ such that Noack is 2750 (CCS at-35 ℃) ^(-0.8) And +/-2. These characteristics allow the formulation of low viscosity engine oils as well as many other high performance lubricant products.

In one embodiment, C16 olefins are used as a feed for the oligomerization reaction. When using C16 olefins as the feed, the hydroisomerized dimer product typically exhibited a KV100 of 4.3 cSt, with a Noack loss of < 8%, and a CCS at-35 ℃ of about 1700 cP. The very low Noack volatility is attributed to the high bubble point and narrow boiling point distribution when compared to other 3.9-4.4cSt synthetic base stocks. This makes the dimer product ideal for use in low viscosity engine oils with stringent volatility requirements. The excellent CCS and pour point characteristics are attributed to the branching characteristics described above. In one embodiment, the dimer product has a pour point ≦ 40 ℃. This is required to pass key engine oil formulation requirements for 0W formulations, including micro rotational viscosity (ASTM D4684) and scanning Brookfield viscosity (ASTM D2983) specifications.

Various embodiments of the process of the present invention are depicted in block diagrams in fig. 4-7.

FIG. 4 depicts a preferred embodiment comprising the selective use of an olefin feed (1) of a mono-olefin or mixture of 14 to 20 carbons in length. In BF ₃ And oligomerizing (2) the olefin in either a semi-batch or CSTR mode in the presence of a promoter (13). Subsequently, unreacted monomeric olefin is removed by distillation (3). Optionally, the unreacted monomers may be recycled back to the oligomerization reactor (12). The dimer and higher oligomers are then subjected to simultaneous saturation (4) and hydroisomerization (5). Cracked light products (11) formed during the hydroisomerization are removed by distillation (6). The remaining oligomers are then separated via distillation (7) into the final dimer (9) and trimer + product (10).

FIG. 5 depicts an embodiment comprising selecting an olefin feed (14) that utilizes a mono-olefin or mixture of 14 to 20 carbons in length. In BF ₃ And an accelerator (24) in either a semi-batch or CSTR modeThe olefin is described. Subsequently, unreacted monomers are removed by distillation (16). Optionally, unreacted olefin monomer may be recycled back to the oligomerization reactor (23). The dimers and higher oligomers are then hydroisomerized (17). Complete saturation of the isomerized oligomers is achieved during the hydroisomerization process (17). Cracked light products (22) formed during the hydroisomerization are removed (18). The remaining oligomers are then separated via distillation (19) into the final dimer (20) and trimer + product (21).

Fig. 6 depicts a variation of the process in which the oligomerization product is saturated (28) and distilled (29) prior to hydroisomerization. The branching proximity of the non-isomerized hydrogenated dimer (30) is 27-35. The non-isomerized dimer (30) and trimer + (35) products are then separately hydroisomerized (31, 36), and the resulting cracked light streams (34, 39) are removed via distillation (32, 37) to produce the final dimer (33) and trimer + (38) products.

Fig. 7 depicts a variation of the process in which prior to hydroisomerization, oligomer distillation (45) is performed to separate the non-isomerized dimers from trimer + oligomers (46, 51). Complete saturation of both dimer and trimer + fractions is achieved during the hydroisomerization process (47, 52). Cracked lights (50, 55) are then removed from the hydroisomerized dimers and trimers by distillation (48, 53) to produce the final dimer (49) and trimer + (54) products.

As mentioned, the resulting hydrocarbon mixture obtained from the process of the present invention has outstanding properties, including very low volatility, good low temperature properties, etc., which are important performance attributes of high quality base stocks. In particular, according to FIMS, the mixture comprises more than 80% of molecules having an even number of carbon numbers. The branching characteristics of the hydrocarbon mixture by NMR indicate BP/BI ≧ 0.6037 (internal alkyl branching per molecule) + 2.0. Further, on average, at least 0.3 to 1.5 internal methyl branches are located more than four carbons from the terminal carbon. These characteristics are shown in figures 1-3 of the drawings. Saturated hydrocarbons with this unique branching structure exhibit a surprising correlation of cold cranking simulated viscosity (CCS) versus Noack volatility (fig. 3), which is beneficial for blending low viscosity automotive engine oils. The following definitions are provided to better understand the uniqueness of the hydrocarbon mixture product achieved by the process of the present invention.

Definition of Hydrocarbon Properties

The following properties are used to describe the novel saturated hydrocarbon mixture:

viscosity is a physical property that measures the flow of a base stock. Viscosity is a strong function of temperature. Two common viscosity measurements are dynamic viscosity and kinematic viscosity. Dynamic viscosity measures the internal resistance to flow of a fluid. Cold Cranking Simulator (CCS) viscosity of engine oil at-35 ℃ is one example of a dynamic viscosity measurement. The international standard unit for dynamic viscosity is Pa · s. The conventional unit used is centipoise (cP), which is equal to 0.001Pa · s (or 1mPa · s). The industry is slowly moving to international standards bodies. Kinematic viscosity is the ratio of dynamic viscosity to density. The international standard unit for kinematic viscosity is mm ² And(s) in the presence of a catalyst. Other common units in the industry are centistokes at 40 ℃ (KV40) and at 100 ℃ (KV100) and saybolt universal viscosity seconds (SUS) at 100 ° F and 210 ° F. Conveniently, 1mm ² The/s is equal to 1 cSt. ASTM D5293 and D445 are measurement methods for CCS and kinematic viscosity, respectively.

Viscosity Index (VI) is an empirical value used to measure the change in kinematic viscosity of a base stock as a function of temperature. The higher the VI, the less the relative change in viscosity with temperature. High VI base stocks are desirable for most lubricant applications, especially for multigrade automotive engine oils and other automotive lubricants that experience large operating temperature variations. ASTM D2270 is a generally accepted method for determining VI.

Pour point is the lowest temperature at which movement of the test specimen is observed. It is one of the most important properties of base stocks because most lubricants are designed to operate in the liquid phase. Low pour points are often desirable, especially in cold climate lubrication. ASTM D97 is a standard manual method of measuring pour point. It is increasingly being replaced by automated methods such as ASTM D5950 and ASTM D6749. ASTM D5950 with a1 ℃ test interval was used for pour point measurements in the examples of this patent.

Volatility is a measure of the loss of oil by evaporation at elevated temperatures. It has become a very important specification due to emissions and operating life concerns, especially for light grade base stocks. The volatility depends on the molecular composition of the oil, especially at the front end of the boiling point curve. Noack (ASTM D5800) is a commonly accepted method for measuring the volatility of automotive lubricants. The Noack test method itself simulates evaporative losses in high temperature use such as an operating internal combustion engine.

The boiling point profile is the boiling point range defined by the True Boiling Point (TBP) at which 5% and 95% of the material evaporates. It is measured by ASTM D2887 herein.

NMR branch analysis:

all branching parameters were measured on hydrocarbons with <1000Br index mg Br/100 g. Branching parameters for hydrocarbon characterization, measured by NMR spectroscopy, include:

branching Index (BI): the percentage of methyl hydrogens present in the chemical shift range 0.5 to 1.05ppm among all hydrogens present in the 1H NMR chemical range 0.5 to 2.1ppm in the isoparaffins.

Branch Proximity (BP): appear at ¹³ Percentage of repeating methylene carbons at C NMR chemical shift 29.8ppm with four or more carbon atoms removed from the end groups or branches.

Internal alkyl carbon: is the number of methyl, ethyl or propyl carbons removed from the terminal methyl carbon by three or more carbons, including 3-methyl, 4-methyl, 5+ methyl, adjacent methyl, internal ethyl, n-propyl and occur in ¹³ Unknown methyl groups with C NMR chemical shifts between 0.5ppm and 22.0ppm, except for the terminal methyl carbon which appears at 13.8 ppm.

5+ methyl carbon: is present in the average isoparaffin molecule ¹³ Number of methyl carbons attached to methine carbons more than four carbons from the end carbon at C NMR chemical shift 19.6 ppm.

The feedstock may be defined in the form of alpha, branched and internal olefins.

Definition of catalyst: butanol and butyl acetate are described as n-butanol and butyl acetate such as n-butyl acetate.

Alpha-olefins: chemical formula C _x Unsaturated hydrocarbons of H2x, characterized by having a double bond in the primary or alpha position and having a linear hydrocarbon chain.

Branched olefins: an olefin in which the carbon structure has one or more tertiary carbons.

Internal olefin: olefins in which the unsaturation is not in a terminal position.

NMR spectra were obtained using a Bruker AVANCE 500 spectrometer using a 5mm BBI probe. Each sample was mixed with CDCl at a ratio of 1:1(wt: wt) ₃ And (4) mixing. ¹ H NMR was recorded at 500.11MHz and 9.0 μ s (30 °) pulses applied at 4s intervals were used and 64 scans were added simultaneously per spectrum. ¹³ C NMR was recorded at 125.75MHz using a 7.0 μ s pulse and applied at 6 second intervals using inverse gated decoupling, and 4096 scans were added simultaneously per spectrum. Adding a small amount of 0.1M Cr (acac) ₃ As relaxant, and TMS as internal standard.

The branching properties of the lubricant base stock samples of the present invention were determined according to the following six-step method. The procedure is provided in detail in US 20050077208a1, which is incorporated herein in its entirety. The following procedure was slightly modified to characterize the sample sets of the present invention:

1) identifying CH branch centers and CH using DEPT pulse sequences ₃ Branch endpoints (Doddrell, D.T.; D.T. Pegg; M.R. Bendall, Journal of Magnetic Resonance 1982, 48, 323 and beyond).

2) The absence of carbon triggering multiple branches (quaternary carbon) was verified using APT pulse sequences (pat, s.l.; wood, Journal of Magnetic Resonance 1982, 46, 535 and beyond).

3) Tabulated values and calculated values are used to assign various branched carbon resonances to specific branched positions and lengths (Lindeman, l.p., Journal of Qualitative Analytical Chemistry 43, 19711245 and beyond; netzel, d.a. et al, Fuel, 60, 1981, 307 and beyond).

Branched NMR chemical shifts (ppm)

Table 2: description of ppm shift of alkyl branching by carbon NMR

Branch of	NMR chemical shifts (ppm)
		2-methyl radical	22.5
3-methyl group	19.1 or 11.4
		4-methyl group	14.0
5+ methyl group	19.6
		Internal ethyl radical	10.8
N-propyl radical	14.4
		Adjacent methyl radical	16.7

4) The relative frequency of branches appearing at different carbon positions is quantified by comparing the integrated intensity of its terminal methyl carbon with the intensity of a single carbon (total carbon per molecule in the mixture). For example, the number of 5+ methyl branches per molecule is calculated from the signal intensity at a chemical shift of 19.6ppm relative to the intensity of a single carbon.

For the unique case of a 2-methyl branch, where both the terminal and branched methyl groups occur at the same resonance position, the intensity is divided by 2 before making branch occurrence frequency calculations.

If the 4-methyl branch score is calculated and tabulated, its contribution to the 5+ methyl group must be subtracted to avoid duplicate counts.

The unknown methyl branches were calculated from the contribution of the signal appearing between 5.0ppm and 22.5ppm, however excluding any branches reported in table 2.

5) The Branch Index (BI) and Branch Proximity (BP) are calculated using the calculations described in U.S. patent No. 6090989, which is incorporated herein by reference in its entirety.

6) The total internal alkyl branches per molecule were calculated by adding the branches found in steps 3 and 4 (excluding the 2-methyl branch). These branches will include 3-methyl, 4-methyl, 5+ methyl, endo-ethyl, n-propyl, adjacent methyl and unknown methyl groups.

FIMS analysis: the hydrocarbon distribution of the present invention is determined by FIMS (field ionization mass spectrometry). FIMS spectra were obtained on a Waters GCT-TOF mass spectrometer. The sample was introduced via a solid probe, which was heated from about 40 ℃ to 500 ℃ at a rate of 50 ℃/min. The mass spectrometer was scanned from m/z40 to m/z1000 at a rate of 5 seconds per decade. The obtained mass spectra were summed to produce one average spectrum which provides the carbon number distribution of paraffins and naphthenes containing up to 6 rings.

Hydrocarbon structure and properties

The structure of the hydrocarbon mixtures disclosed herein is characterized by FIMS and NMR. FIMS analysis confirmed that greater than 80% of the molecules in the hydrocarbon mixture had an even number of carbon numbers.

The unique branched structure of the hydrocarbon mixtures disclosed herein is characterized by NMR parameters such as BP, BI, internal alkyl branching, and 5+ methyl. The BP/BI of the hydrocarbon mixture is ≥ 0.6037 (internal alkyl branch per molecule) + 2.0. The hydrocarbon mixture has an average of 0.3 to 1.5 methyl groups per molecule.

The hydrocarbon mixture can be divided into two carbon ranges based on carbon number distribution: C28-C40 carbons, and greater than or equal to C42. Typically, about or greater than 95% of the molecules present in each hydrocarbon mixture have a carbon number within the specified range. Representative molecular structures in the C28-C40 range can be proposed based on NMR and FIMS analysis. Without wishing to be bound by any particular theory, it is believed that the structures produced by the oligomerization and hydroisomerization of olefins have methyl, ethyl, butyl branches distributed throughout the structure, and that the branching index and branching proximity contribute to the surprisingly good low temperature properties of the product. Exemplary structures in the hydrocarbon mixtures of the present invention are as follows:

the unique branched structure and narrow carbon distribution of the hydrocarbon mixtures make them suitable for use as high quality synthetic base oils, especially for low viscosity engine oil applications. The hydrocarbon mixture exhibits:

KV100 is 3.0-10.0 cSt;

pour point from-20 ℃ to-55 ℃; and

correlation of Noack with CCS at-35 ℃ so that Noack is between 2750 (CCS at-35 ℃) ^(-0.8) Between + -2.

The correlation of Noack and CCS for the hydrocarbon mixtures is shown in figures 3 and 4. In each figure, the top line represents Noack-2750 (CCS at-35 ℃) ^(-0.8) +2 and bottom plot represent Noack ═ 2750 (CCS at-35 ℃) ^(-0.8) -2. More preferably, the hydrocarbon mixture has a correlation of Noack and CCS at-35 ℃ such that Noack is between Noack-2750 (CCS at-35 ℃) ^(-0.8) +0.5 and Noack-2750 (CCS at-35 deg.C) ^(-0.8) -2. It has been found that the hydrocarbon mixtures closer to the origin in fig. 3 and 4 are more favorable for low viscosity engine oils due to low volatility and reduced viscosity at-35 ℃.

In addition to the above-described BP/BI, internal alkyl branching per molecule, 5+ methyl branching per molecule and Noack/CCS correlation properties, a hydrocarbon mixture according to the present invention having a carbon number in the range of C28-C40 and in another embodiment in the range of C28-C36, or in another embodiment a molecule having a carbon number of C32, will typically exhibit the following properties:

KV100 is 3.0-6.0 cSt;

VI is 11ln (BP/BI) +135 to 11ln (BP/BI) + 145; and

pour points were 33ln (BP/BI) -45 to 33ln (BP/BI) -35.

In one embodiment, the KV100 of the C28 to C40 hydrocarbon mixture is from 3.2 to 5.5 cSt; in another embodiment KV100 is from 4.0 to 5.2 cSt; and in another embodiment from 4.1 to 4.5 cSt.

The VI of the C28-C40 hydrocarbon mixture is 125-155 in one embodiment and 135-145 in another embodiment.

The pour point of the hydrocarbon mixture is in one embodiment from 25 ℃ to-55 ℃ and in another embodiment from 35 ℃ to-45 ℃.

The boiling point range of the C28-C40 hydrocarbon mixture is in one embodiment no greater than 125 ℃ (TBP at 95% to TBP at 5%), as measured by ASTM D2887; in another embodiment no greater than 100 ℃; in one embodiment no greater than 75 ℃; in another embodiment no greater than 50 ℃; and in one embodiment no greater than 30 deg.c. In preferred embodiments, those having a boiling point range of no greater than 50 ℃ and even more preferably no greater than 30 ℃ for a given KV100 produce surprisingly low Noack volatility (ASTM D5800).

The C28-C40 hydrocarbon mixture in one embodiment has a Branching Proximity (BP) of 14 to 30 and a Branching Index (BI) of 15 to 25; and in another embodiment BP is from 15 to 28 and BI is from 16 to 24.

The C28-C40 hydrocarbon mixture has a Noack volatility (ASTM D5800) of less than 16 wt% in one embodiment; in one embodiment less than 12 wt%; in one embodiment less than 10 wt%; in one embodiment less than 8 wt% and in one embodiment less than 7 wt%. The C28-C40 hydrocarbon mixture also has a cP of less than 2700 in one embodiment; less than 2000cP in another embodiment; less than 1700cP in one embodiment; and a CCS viscosity at-35 deg.C of less than 1500cP in one embodiment.

In addition to the above-mentioned BP/BI, internal alkyl branching per molecule, 5+ methyl branching per molecule, and the correlation of Noack to CCS at-35 ℃, hydrocarbon mixtures in the carbon number range of C42 and greater will generally exhibit the following characteristics:

KV100 is 6.0-10.0 cSt;

VI is 11ln (BP/BI) +145 to 11ln (BP/BI) + 160; and

pour points were 33ln (BP/BI) -40 to 33ln (BP/BI) -25.

Hydrocarbon mixtures containing C42 carbons or greater have KV100 in one embodiment from 8.0 to 10.0cSt, and in another embodiment from 8.5 to 9.5 cSt.

The VI of the hydrocarbon mixture having 42 carbons or more is in one embodiment 140-170; and in another embodiment 150-.

Pour point is in one embodiment-15 ℃ to-50 ℃; and in another embodiment from-20 deg.C to-40 deg.C.

In one embodiment, the BP of a hydrocarbon mixture containing 42 carbons or more is from 16 to 30 and the BI is from 15 to 25. In another embodiment, the hydrocarbon mixture has a BP of from 18 to 28 and a BI of from 17 to 23.

In general, the two hydrocarbon mixtures disclosed above exhibit the following characteristics:

according to FIMS, at least 80% of the molecules have an even number of carbon numbers;

KV100 is 3.0-10.0 cSt;

pour point from-20 ℃ to-55 ℃;

correlation of Noack with CCS at-35 ℃ so that Noack is between 2750 (CCS at-35 ℃) ^(-0.8) Plus or minus 2;

BP/BI ≥ 0.6037 (internal alkyl branch) +2.0 per molecule; and

an average of 0.3 to 1.5 5+ methyl branches per molecule.

Lubricant formulations

The hydrocarbon mixtures produced by the process of the present invention can be used as lubricant base stocks to formulate finished lubricant products containing additives. In certain variations, the base stock prepared according to the methods described herein is blended with one or more additional base stocks such as one or more commercially available PAOs, one or more gas-to-liquid (GTL) base stocks, one or more mineral base stocks, vegetable oil base stocks, algae-derived base stocks, a second base stock described herein, or any other type of renewable base stock. Any effective amount of additional base stock may be added to achieve a blended base oil with the desired properties.

The invention will be further illustrated by the following examples which are not intended to be limiting.

Examples

Examples 1-6(C28-C40 Hydrocarbon mixtures)

Example 1

1-hexadecenes with less than 8% branching and internal olefins at BF ₃ And a cocatalyst combination of butanol and butyl acetate. The reaction was maintained at 20 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 90 minutes. Unreacted monomer was then distilled off, leaving less than 0.1% of the monomer in the distillation bottoms. The dimer was then separated from the trimer + by distillation and less than 5% of the trimer remained in the dimer fraction.

The dimer is then hydroisomerized with an alumina-bound noble metal-impregnated MRE structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 307 ℃. The cracked molecules were separated from the hydroisomerized C16 dimers using an in-line stripper.

Example 2

The oligomerization and oligomer distillation were performed as in example 1. The dimer is then hydroisomerized with an alumina-bound noble metal-impregnated MRE structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 313 ℃. The cracked molecules were separated from the hydroisomerized C16 dimers using an in-line stripper.

Example 3

Oligomerization and oligomer distillation were performed as in example 1. The dimer is then hydroisomerized with an alumina-bound noble metal-impregnated MRE structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 324 ℃. The cracked molecules were separated from the hydroisomerized C16 dimers using an in-line stripper.

Example 4

The oligomerization and oligomer distillation were performed as in example 1. The dimer is then hydroisomerized with an alumina-bound noble metal-impregnated MTT structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 316 ℃. The cracked molecules were separated from the hydroisomerized C16 dimers using an in-line stripper.

Example 5

The oligomerization and oligomer distillation were performed as in example 1. The dimer is then hydroisomerized with a noble metal-impregnated MTT structure type aluminosilicate catalyst bound to alumina. The reaction was carried out in a fixed bed reactor at 500psig and 321 ℃. The cracked molecules were separated from the hydroisomerized C16 dimers using an in-line stripper.

Example 6

Oligomerization and oligomer distillation were performed as in example 1. The dimer is then hydroisomerized with an alumina-bound noble metal-impregnated MTT structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 332 ℃. The cracked molecules were separated from the hydroisomerized C16 dimers using an in-line stripper.

Examples 7 to 12 (C.gtoreq.42 hydrocarbon mixture)

Example 7

1-hexadecenes with less than 8% branching and internal olefins at BF ₃ And a cocatalyst combination of butanol and butyl acetate. The reaction was maintained at 20 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 90 minutes. Unreacted monomer is then distilled away, leaving less than 0.1% of the monomer in the distilled substrate. Subsequent distillation is performed to separate the dimer from the trimer and higher oligomers, with the dimer formed having less than 5% trimer.

The trimer and higher oligomer (trimer +) fractions are then hydroisomerized with an alumina-bound noble metal-impregnated MRE structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 313 ℃. The cracked molecules were separated from the hydroisomerized C16 trimer + using an in-line stripper.

Example 8

The oligomerization and subsequent distillation were carried out in the same manner as in example 7. The trimer + fraction is then hydroisomerized with an alumina-bound noble metal-impregnated MRE structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 318 ℃. The cracked molecules were separated from the hydroisomerized C16 trimer + using an in-line stripper.

Example 9

The oligomerization and subsequent distillation were carried out in the same manner as in example 7. The trimer + fraction is then hydroisomerized with a noble metal-impregnated MRE structure type aluminosilicate catalyst incorporating alumina. The reaction was carried out in a fixed bed reactor at 500psig and 324 ℃. The cracked molecules were separated from the hydroisomerized C16 trimer + using an in-line stripper.

Example 10

The oligomerization and subsequent distillation were carried out in the same manner as in example 7. The trimer + fraction is then hydroisomerized using an alumina-bound noble metal-impregnated MTT structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 321 ℃. The cracked molecules were separated from the hydroisomerized C16 trimer + using an in-line stripper.

Example 11

The oligomerization and subsequent distillation were carried out in the same manner as in example 7. The trimer + fraction is then hydroisomerized using an alumina-bound noble metal-impregnated MTT structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 327 ℃. The cracked molecules were separated from the hydroisomerized C16 trimer + using an in-line stripper.

Example 12

The oligomerization and subsequent distillation were carried out in the same manner as in example 7. The trimer + fraction is then hydroisomerized using an alumina-bound noble metal-impregnated MTT structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 500psig and 332 ℃. The cracked molecules were separated from the hydroisomerized C16 trimer + using an in-line stripper.

Examples 13 and 14

Hexadecenes at BF having 75% alpha olefins and less than 8% branched and internal olefins ₃ And a cocatalyst combination of butanol and butyl acetate. The reaction was maintained at 50 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 90 minutes. Unreacted monomer was then distilled off, leaving less than 0.1% monomer distillation bottoms.

The dimers and higher oligomers are then hydroisomerized with an alumina-bound noble metal-impregnated MRE structure type aluminosilicate catalyst. The reaction was carried out in a fixed bed reactor at 350psig and 300 ℃. The cracked molecules were separated from the hydroisomerized C16 dimers using an in-line stripper. Distillation was then performed to separate the dimer from the trimer +, and less than 5% of the trimer remained in the dimer fraction. The distillation fraction containing trimer + was examined and reflected as example 14.

The results of the examination of the hydrocarbon mixtures obtained in examples 1 to 14 are summarized in table 3 below.

TABLE 3

NM: not measured

In FIGS. 1 and 2, the correlation between BP/BI and the internal alkyl branches per molecule and the 5+ methyl branches per molecule, respectively, of the hydrocarbon mixture achieved by the process of the present invention is demonstrated. Figure 3 graphically depicts the correlation between NOACK volatility of the obtained hydrocarbon products and CCS at-35 ℃. The data in table 3 confirms these unique correlations and properties.

Examples 15 to 21

The effect of boron trifluoride oligomerization temperature on oligomer structure and performance was investigated. It was found that higher reaction temperatures increased the isomerization that occurred during oligomerization. To directly observe this effect by NMR, the oligomer product was saturated and distilled into dimer and trimer + fractions. The proximity of the branches was measured for each dimer fraction example. The results for samples 15-21 are shown in Table 4 below.

TABLE 4

It can be seen from the data that as the reaction temperature increases, the linearity of the fraction, as measured by branch proximity, decreases. This indicates an increase in the number of branches along the carbon backbone. The increased branching produced during high temperature oligomerization does not provide the desired number of 5+ methyl branches per molecule for the dimer fraction needed to achieve the desired pour point. The desired 5+ methyl branching is achieved by hydroisomerization of the oligomer product.

The increase in methyl branching during oligomerization will produce a hydroisomerized product with incorrect branching and undesirable physical properties. The hydrogenated dimer requires a branching proximity of 27-35 prior to hydroisomerization.

Example 15

Hexadecene with 93% alpha olefins and less than 8% branched and internal olefins at BF ₃ Oligomerization with a co-catalyst combination of butanol and butyl acetate. The reaction was maintained at 30 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 90 minutes. Unreacted monomer is then distilled away, leaving less than 0.1% of monomer distillation bottoms. Distillation was then performed to separate the dimer from the trimer +, and less than 5% of the trimer remained in the dimer fraction. The dimer fraction is subsequently hydrogenated without isomerization.

Example 16

Hexadecenes at BF having 93% alpha olefins and less than 8% branched and internal olefins ₃ Oligomerization with a co-catalyst combination of butanol and butyl acetate. The reaction was maintained at 50 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 90 minutes. Unreacted monomer is then distilled away, leaving less than 0.1% of monomer distillation bottoms. Distillation is then performed to separate the dimer from the trimer +, and less than 5% of the trimer remains in the dimer fraction. The dimer fraction is subsequently hydrogenated without isomerization.

Example 17

Hexadecenes at BF having 93% alpha olefins and less than 8% branched and internal olefins ₃ Oligomerization with a co-catalyst combination of butanol and butyl acetate. The reaction was maintained at 80 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 90 minutes. Unreacted monomer was then distilled off, leaving less than 0.1% monomer distillation bottoms. Distillation was then performed to separate the dimer from the trimer +, and less than 5% of the trimer remained in the dimer fraction. The dimer fraction is subsequently hydrogenated without isomerization.

Example 18

Hexadecenes at BF having 75% alpha olefins and less than 1% branched and internal olefins ₃ Oligomerization with a co-catalyst combination of butanol and butyl acetate. The reaction was maintained at 50 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 120 minutes. Unreacted monomer was then distilled off, leaving less than 0.1% monomer distillation bottoms. Distillation is then performed to separate the dimer from the trimer +, and less than 5% of the trimer remains in the dimer fraction. The dimer fraction is subsequently hydrogenated without isomerization.

Example 19

Hexadecenes at BF having 60% alpha olefins and less than 1% branched and internal olefins ₃ Oligomerization with a co-catalyst combination of butanol and butyl acetate. The reaction was maintained at 50 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 120 minutes. Then distilling off the unreacted monomersBulk, leaving less than 0.1% monomer distillation substrate. Distillation is then performed to separate the dimer from the trimer +, and less than 5% of the trimer remains in the dimer fraction. The dimer fraction is subsequently hydrogenated without isomerization.

Example 20

Hexadecenes at BF having 60% alpha olefins and less than 1% branched and internal olefins ₃ Oligomerization with a co-catalyst combination of butanol and butyl acetate. The reaction was maintained at 30 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 120 minutes. Unreacted monomer was then distilled off, leaving less than 0.1% monomer distillation bottoms. Distillation was then performed to separate the dimer from the trimer +, and less than 5% of the trimer remained in the dimer fraction. The dimer fraction is subsequently hydrogenated without isomerization.

Example 21

Hexadecenes at BF having 45% alpha olefins and less than 1% branched and internal olefins ₃ Oligomerization with a co-catalyst combination of butanol and butyl acetate. The reaction was maintained at 50 ℃ during the semi-continuous addition of olefin and cocatalyst. The residence time was 120 minutes. Unreacted monomer was then distilled off, leaving less than 0.1% monomer distillation bottoms. Distillation was then performed to separate the dimer from the trimer +, and less than 5% of the trimer remained in the dimer fraction. The dimer fraction is subsequently hydrogenated without isomerization.

Claims (16)

1.A method of making a base stock comprising:

(i) providing an olefin feedstock comprising C14 to C20 olefins comprising less than 40 wt% branched olefins and greater than 40 wt% alpha olefins;

(ii) oligomerizing the olefin feedstock using a boron trifluoride catalyst at a reaction temperature of 20 to 60 ℃ while controlling reaction conditions to obtain an intermediate having a dimer fraction such that the dimer fraction of the intermediate, when saturated without hydroisomerization, produces saturated dimers having a branching proximity of 27 to 35; and

(iii) (iii) hydroisomerizing at least a portion of the intermediate obtained from step (ii) using a metal-impregnated one-dimensional 10-membered ring zeolite catalyst to achieve a C28+ product having BP/BI ≧ 0.6037 × (internal alkyl branches per molecule) +2.0 and having an average of 0.3-1.5 methyl branches at the 5 th or greater position per molecule.

2. The process of claim 1, wherein the olefin feedstock comprises greater than 50 wt% alpha olefins.

3. The process of claim 2, wherein the olefin feedstock comprises less than 8 wt% branched olefins.

4. The process of claim 1, wherein the olefin feedstock comprises greater than 70 wt% alpha olefins.

5. The process of claim 1, wherein the boron trifluoride catalyst used in the oligomerization of (ii) further comprises an alcohol promoter and an ester promoter.

6. The process of claim 1, wherein the residence time for oligomerization is 60-180 minutes.

7. The process of claim 2, further comprising, prior to step (iii), recovering the intermediate, removing unreacted monomer from the intermediate, and recovering the resulting intermediate.

8. The process of claim 7, wherein the removed unreacted monomer is recycled to the olefin feed of step (i).

9. The process of claim 7, further comprising hydrogenating the resulting intermediate to produce a hydrogenated intermediate, which is then subjected to the hydroisomerization of step (iii); and

recovering the hydroisomerized product and separating the hydroisomerized product into a fraction comprising more than 95 wt% of dimers having a maximum carbon number of 40 and a fraction comprising more than 95 wt% of trimers and higher oligomers having a minimum carbon number of 42.

10. The process according to claim 7, wherein the resulting intermediate is separated into a fraction comprising more than 95 wt% of dimers having a maximum carbon number of 40, and a fraction comprising more than 95 wt% of trimers and higher oligomers having a minimum carbon number of 42.

11. The process of claim 10, further comprising separately hydroisomerizing each of said fractions.

12. The process of claim 7, wherein the resulting intermediate is further hydrogenated to produce a hydrogenated intermediate, wherein the hydrogenated intermediate comprises a dimer having a maximum carbon number of 40 and a branching proximity of 28-32.

13. The process of claim 2 wherein the hydroisomerization is at a pressure of 100-; at a temperature of 290 ℃ and 350 ℃ and a hydrogen flow rate of 500 ℃ and 3500 scf/bbl.

14. The method of making a base stock according to claim 2, further comprising:

in (i), providing an olefin feedstock comprising less than 8 wt% branched monomeric olefins and greater than 50 wt% monomeric alpha olefins, and the carbon number of the monomeric olefins is C14-C20;

in (ii), the olefin feed of (i) is reacted in BF ₃ Carrying out said oligomerization reaction in a semi-batch or continuously stirred tank reactor over a catalyst and BuOH and BuAc co-catalysts at a reaction residence time of 60 to 180 minutes;

(iii) recovering the oligomerised intermediate in step (ii), removing unreacted monomer by distillation, recovering the intermediate resulting from the distillation; and subjecting the resulting intermediate recovered from said distillation to hydrogenation;

recovering the hydrogenated hydrogenation product and over the metal impregnated one dimensional 10 member ring zeolite at a pressure of 100-; 290 ℃ and 350 ℃; and 500-;

(ii) recycling the unreacted monomer removed in the distillation to the olefin feedstock in (i); and

separating a dimer fraction and a trimer and higher oligomer fraction from the hydroisomerized product, and said dimer fraction comprising greater than or equal to 95 wt% dimers having a maximum carbon number of 40.

15. The method of making a base stock according to claim 2, further comprising:

in (i), providing an olefin feedstock comprising less than 8 wt% branched monomeric olefins and greater than 50 wt% monomeric alpha olefins, and the carbon number of the monomeric olefins is C14-C20;

in (ii), the olefin feed of (i) is reacted in BF ₃ Oligomerizing in a semi-batch or continuous stirred tank reactor over a catalyst and BuOH and BuAc co-catalysts at a reaction residence time of 60-180 minutes;

(iii) recovering the oligomerised intermediate in step (ii) and removing unreacted monomer by distillation; recovering the bottoms product of the distillation and over the metal impregnated one dimensional 10 membered ring zeolite at a pressure of 100psig to 800 psig; 290 ℃ and 350 ℃; and 500-3500scf/bbl of hydrogen flow rate;

(ii) recycling the unreacted monomer removed in the distillation to the olefin feed in (i); and

recovering a hydroisomerized product of the hydroisomerisation and separating said hydroisomerisation product into a dimer fraction comprising dimers having a carbon number of from C28 to C40, and a trimer and higher oligomer fraction comprising compounds having a carbon number of 42 and higher.

16. The method of making a base stock according to claim 2, further comprising:

in (i), providing an olefin feedstock comprising less than 8 wt% branched monomeric olefin and greater than 50 wt% monomeric alpha olefin, and the carbon number of the monomeric olefin is C14-C20;

in (ii), the olefin feed of (i) is reacted in BF ₃ Oligomerizing in a semi-batch or continuously stirred tank reactor over a catalyst and BuOH and BuAc co-catalysts at a reaction residence time of 60-180 minutes;

(iii) recovering the oligomerized intermediates of step (ii), removing unreacted monomer by distillation, and recovering a bottom distillation product;

separating a dimer fraction and a trimer and higher oligomer fraction from the bottom distillation product, and the dimer fraction comprises greater than or equal to 95% of compounds having a maximum carbon number of 40, and the trimer and higher oligomer fraction comprises compounds having a carbon number of 42 and greater; and

on a metal impregnated one dimensional 10 member ring zeolite at a pressure of 100-; 290 ℃ and 350 ℃; and 500 to 3500scf/bbl of hydrogen flow rate to hydroisomerize each of the dimer fraction and trimer and higher oligomer fractions, respectively.

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